A new species of Megalotocepheus from China, Megalotocepheus (Archegotocepheus) octocapillus sp. nov., is found and described based on adult material collected from Southwest China. It can be distinguished from other known species of Megalotocepheus by combination of following characters: eight pairs of notogastral setae, short and rounded sternal apodeme, a pair of arcuate marginalis laterally in upper parts of subcapitulum, lyrifissure ip located between p₁ and p₂, leg setae pv” on tarsi III–IV and v” on tibia III–IV pinniform. Meanwhile, Megalotocepheus (Archegotocepheus) singularis Mahunka, 1988 is reported in China for the first time. Neotypes of Megalotocepheus (Megalotocepheus) fornicatus Wen, 1999 and Megalotocepheus (Megalotocepheus) hainanensis Wen & Zhao, 1993 were designated, and supplementary descriptions of M. (M.) fornicatus and M. (M.) hainanensis are given. Megalotocepheus (M.) tianshanicus (Krivolutsky, 1969) is transferred to the genus Fissicepheus, M. (M.) ceylonicus Balogh, 1970 and M. (M.) loksai Balogh, 1970 are transferred to the genus Otocepheus. A key to the known taxa of Megalotocepheus is provided.